METHODS

Bulk carbonate ¹³C and ¹⁸O values were measured on total of 174 upper Campanian and Maastrichtian samples distributed among the five sites drilled during ODP Leg 207. Ages were estimated using shipboard foraminiferal and nannofossil datums (Erbacher, Mosher, Malone, et al., 2004). From each sample, ~75 µg of material was scraped from a clean, dried (<50°C) surface. This powder was loaded into a single reaction vessel and analyzed on a Kiel III carbonate device in line with a Finnegan Delta Plus isotope ratio mass spectrometer at the University of Missouri Biogeochemistry Isotope Laboratory. Results are reported in standard delta notation relative to the Vienna Peedee belemnite standard and were normalized to a nominal value of ¹³C = 1.95 and ¹⁸O = –2.20 for the National Bureau of Standards NBS-19 standard based on the average of multiple replicates of this standard run with the samples. Long-term precision for this standard (uncorrected) is <0.03 and <0.06 (1) for ¹³C and ¹⁸O, respectively.